During my talk at the Alabama Code Camp, I demonstrated how you can host a SOAP web service in a WinForms application (or a Windows Service, etc.). However, my solution required the use of SOAP over TCP, which does make it less interoperable.
William Stacey himself hasn’t been idle either lately. He posted an improved custom solution to create a security context token on Channel 9. His first solution can be found on his blog and as a complete sample in my Alabama Code Camp downloads (Demo 2). I will probably change an implementation of web services I was working on to this SRP implementation. It is standards-based (which makes long-term maintenance, including maintenance by others) easier and promotes better security because the protocol has seen extensive reviews by the security community.